Motorcycle Repair: vacume jumps at idle, yamaha yzf600r, panka

Question
I have a 1999 Yamaha yzf600r and I cannot sync the carbs because the vacume jumps to fast to read the gauge. Is this normal or do I need a special gauge with dampers ?

Answer
Mark, What you'll need to do is have the idle set to a point where the guage jumps around the least.

The mercury bouncing you are experiencing is quite normal especialy for a bike such as yours with a higher compression.

What youre looking for is for 1 and 3 to bounce about the same as well as 2 and 4, then the 2 sets can be sync'd to match.. Its the range within the bouncing youre looking to achieve..

Hope this helps!

~Mark Panka